/Engine/Source/Runtime/Engine/Classes/Engine/Texture.h
Scan the texture source pixels to compute the min & max values of the RGBA channels. Uses texture source, not available in runtime games. Causes texture source data to be loaded, is computed by scanning pixels when called. Will set Min=Max=zero and return false on failure
bool ComputeTextureSourceChannelMinMax ( [FLinearColor](API\Runtime\Core\Math\FLinearColor) & OutColorMin, [FLinearColor](API\Runtime\Core\Math\FLinearColor) & OutColorMax ) const